Other Binders - Stabilization and Solidification of Hazardous, Radioactive, and Mixed Wastes - page 140

TABLE 6.5.2
Characteristics of Aluminosilicate Concretes

Fraction
Water-
Leachable d
M +, %

Specimen a
(Type, Pozzolan,
Activator, Cure)

Ion Exchange
Capacity e
meq/g

UCS b
MPa

Meq/gram c
Alkali (M+)

IX cap/M +
%

HC , MK,18.7 M NaOH,
45 min @ 200°C

14.5 5.9 6.1 1.12 19.1

GP , MK+calcine, 7.9 M
Na + 4.1 M Si, 3 hr @
70°C

9.0 4.36 17.8 1.11 25.3

GP , FA+calcine, 7.9 M
Na + 4.1 M Si, 3 hr @
70°C

11.0 4.4 33 0.25 5.6

GP , FA, 8 M KOH, 3 hr
@ 70°C

10.6 1.1 87.5 0.047 4.3

GP, FA, 8 M K + 2 M Si,
3 hr @ 70°C

25 1.06 71.8 0.106 9

GP , MK, 8 M NaOH, 3
hr @ 70°C

6.6 2.45 38.8 0.62 25.1

GP , MK, 8 M Na + 2 M
Si, 2 hr @ 200C

3.4 2.54 12.2 0.81 31.5

Commercial Type 4A-8
Mole Sieve

NA 4.5 6.0 2.63 58.3

MK only NA < 0.1 NA 0.033 NA

FA only NA < 0.1 100 0.001 0.01

Raw “steam reformer”
calcine

NA 5.97 3.9 0.013 0.2

a HC = hydroceramic; GP = geopolymer; MK = metakaolin (42% Al 2 O 3 ); FA = Handy™ Class F fly
ash (15% Al 2 O 3 ); “calcine” = “bed” fraction of the product made by fluidized bed steam-reformation
of an INEEL SBW stimulant slurried with kaolin; activators were made by boiling silica fume in
concentrated Na/K hydroxide solutions and then diluting to the indicated M + /Si concentrations.
b Unconfined compressive strength determined with a homemade tester and tiny specimen (for com-
parative purposes only).
c Total alkali in the formulation.
d Determined by passing 10 bed volumes of 1 M NH 4 Cl through the same powder, rinsing with water,
displacing the ammonium ion with ten bed volumes of 1 M NaNO 3 , and then determining it in the eluate.
e Determined by measuring the amount of alkali in 25 bed volumes of ~90°C water that had been
passed through the powdered (50- to 212-micron) sample.

hydroxide dissolved in enough water to produce a stiff paste. The metakaolin does
not have to be particularly pure nor ground fine. Suitable material can be cheaply
produced (~$70/ton) by processing crude kaolin in a “cool” (~700°C) cement kiln,
then grinding it, just as clinker is ground into portland cement. The caustic “activator”
need not be pure either. The “waste” NaOH existing within the DOE Complex can
be profitably employed to make HC waste forms. For example, the INEEL recently